Ctenochiton serratus Green, 1904

Hodgson, Chris, 2020, A review of neococcid scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) based on the morphology of the adult males, Zootaxa 4765 (1), pp. 1-264 : 236-238

Ctenochiton serratus Green ( Fig. 92 )

Ctenochiton serratus Green 1904 , 67. Type data: Australia, Victoria, Warranambool, on Styphelia sp. Syntypes, female. Type depository: BMNH.

Material examined. Australia, Warranambool, on Styphelia sp. ( Epacridaceae ), no date, C. French, no. 34 ( ASCU): 2/2ad ♂♂ (1 specimen in the process of moulting, complete but wings not expanded; other well sclerotised but head separated from body but with one wing almost fully expanded; fair; both covered in areas of wax.)

Mounted material. Rather small, total body length about 1375 μm, width across triangular plates about 345 μm; antennae each a little more than 1/2 total body length; head with four pairs of simple eyes; head and rest of body with few setae; hair-like setae (hs) easily separated from fleshy setae (fs); fs on both body and appendages more abundant than hs; procoxae without stout bristles; trochanterofemur articulation clear. Abdominal caudal extensions on VIII rounded; glandular pouches present but glandular pouch setae short.

Head. Rounded; length 240–250 μm; width across genae 175–210 μm. Median crest well developed dorsally, with narrow reticulate striations; postoccipital ridge absent; with 3–5 fs + 2 or 3 hs dorsal head setae on each side. Mid-cranial ridge absent dorsally; ventrally, mid-cranial ridge narrow but well-defined, extending posteriorly from lateral arms of mid-cranial ridge almost to ocular sclerite; with a lightly reticulated margin; with 1–3 fs + 1 or 2 hs ventral mid-cranial ridge setae. Preocular ridge dorsally quite long, ventrally about 2/3rds way to ventral mid-cranial ridge. Genae large and membranous, with some quite large reticulations, each with rather wavy margins and several inner microridges; with 1 fs genal seta on each side. Eyes: four pairs of round to slightly oval simple eyes; dorsal and ventral eyes larger than lateral pairs: dorsal eyes and ventral eyes each about 45 μm wide, lateral simple eyes each 35–40 μm wide. Ocelli each oval, 18–23 μm long, almost completely surrounded by dorsal end of postocular ridge. Ocular sclerite lightly polygonally reticulated, each reticulation with few or no inner microridges. Postocular ridge extending medially to each ocellus, where divides with an anterior and a posterior arm which meet dorsally, with no further extension. Dorsal ocular setae: 0 or 1 pair fs. Ventral head setae rather few, with 7–12 fs + 0–2 hs on each side; with none posterior to ventral eyes. Tentorial bridge possibly weak. Cranial apophysis quite broad and bifid.

Antennae: 10 segmented and filiform. Scape: 45 μm long, 50 μm wide, with 3 hs. Pedicel: 36–48 μm long, 40–47 μm wide, with a few faint microridges; with 4 or 5 fs + 0 or 1 hs; campaniform pore not detected. Segments IV–X each 20–23 μm wide; length of fs about 30 μm; lengths (μm): III 70–85; IV 115–125; V 105–115; VI 85–100; VII 95–110; VIII 80–82; IX 75–85; X 70–75; approximate number of setae per segment: III 3–5 fs +1–5 hs; IV–IX each with 14–24 fs; segments VIII & IX each with 1 antennal bristle (ab) barely differentiated from fs; X with 8 fs, 2 long ab, 1 short ab, plus 3 capitate setae (caps).

Thorax. Prothorax: pronotal ridge well developed but not fused medially; pronotal sclerite very broad; without lateral pronotal setae. Post-tergites not detected; without post-tergital setae. Median pronotal (mpns) and other dorsal and pleural setae absent. Proepisternum + cervical sclerite well developed. Sternum with a strong transverse ridge; median ridge not reaching transverse ridge posteriorly but moderately developed; sternite with some radial dermal ridges; with 3–5 fs + 2 hs prosternal setae on each side of median ridge; anteprosternal setae and antemesospiracular setae absent.

Mesothorax: probably convex in life; prescutum wider than long, 80–83 μm long, 155–175 μm wide; sclerotised, with obscure nodulations; prescutal setae absent; prescutal ridge and prescutal suture well developed. Scutum: median membranous area probably 75–85 μm long, 165–175 μm wide, with strong marginal ridges; with 1 small fs + 5–10 small hs scutal setae; scutum without polygonal nodulations laterad to scutellum. Scutellum 50–66 μm long, 140–165 μm wide; with a large foramen; scutellar setae absent. Mesepisternum not nodulated. Postalare probably with reticula- tions at anterior end; without postalare setae. Basisternum 135–140 μm long, 230–260 μm wide; median ridge well developed, but incomplete on one specimen; bounded anteriorly by strong marginal ridges and posteriorly by strong precoxal ridges; without basisternal setae; lateropleurite broad, with a strong extension from marginal ridge along anterior border; furca well developed and extending anteriorly to about 2/3rds–4/5ths to marginal ridge. Subepisternal ridge well developed. Mesothoracic spiracle: width of peritreme 23–28 μm. Postmesospiracular setae absent. Ante- metaspiracular setae absent. Mesopostnotum normally developed. Tegula without tegular setae.

Metathorax: with 0 or 1 hs metatergal setae on each side. Dorsospiracular setae 1–3 fs per side. Metapostnotum small. Dorsal part of metapleural ridge absent; ventral part well developed; metepisternum unsclerotised, with about 11 fs + 1 hs postmetaspiracular setae; metepimeron short, without setae. Metathoracic spiracle: width of peritreme 25–28 μm. Metasternum membranous and not reticulated. With 12–14 fs anterior metasternal and 10 or 11 fs posterior metasternal setae on each side.

Wings: hyaline; of moderate length and width, each about 1.2 mm long and 480 μm wide (ratio of length to breadth 1:0.39). Alar lobe, alar setae and sensoria absent. Hamulohalteres absent.

Legs: subequal in size; all segments with many setae, mainly fs. Coxae: length (μm): I 90–95, II 85–95, III 80–100; each procoxa without coxal bristles, but all coxae with a long coxal seta about 50 μm long; metacoxa with many fs + 5 or 6 hs. Trochanterofemur with distinct segmentation; length (μm): I 200–245; II 180–206, III 185–206; each trochanter with a line of small campaniform sensilla; long trochanteral seta short, about 53 μm long; metatro- chanter with several fs + 2 hs; each femur with many fs + about 17 hs. Tibia long: length (μm) I 235–255; II 215–250; III 225–270; metatibia with many fs + a few hs, becoming spur-like distally on ventral margin; apical spur long and strong, each 23–30 μm long. Tarsi: lengths (μm): I 85–115; II 105–115; III 105–115; metatarsi with several fs, a few hs + some spur-like setae; tarsal campaniform pore absent; distal tarsal spur about 18 μm long; tarsal digitules just a little longer than claw. Claws short, each 23–27 μm long, subequal to width of tarsi, possibly with a minute denticle; claw digitules both with rather small capitate apices and longer than claw.

Abdomen. Segments I–VIII: tergites perhaps only present on VIII; sternites only apparent on segments VII and VIII, but that on VIII more distinct. Segment VIII unusually long. Caudal extensions of segment VII absent; those on segment VIII rounded, with 3 shortish hs pleural setae. Dorsal abdominal setae few, with 1 pair of hs on segments V–VII; ante-anal setae on VIII absent. Pleural setae: dorsal pleural setae: I–V each with 0; VI & VII each with 1 or 2 fs + 1 hs; ventral pleural setae (vpls): I–IV each with 0; V 1 fs; VI 1 fs + 1 hs; VII 3 fs + 1 hs. Ventral abdominal setae (on each side): II & III each with 3 fs + 1 hs; IV 1 fs + 2 hs, V & VI each with 1 fs + 1 hs, VII 0 fs + 1 hs. Segment VIII with 2 fs + 1 hs dorsal pleural setae and 1 hs ventral pleural seta. Glandular pouches deep, each pouch divided into an inner and an outer section; glandular pouch setae proportionately rather short, each 87–120 μm.

Genital segments. Segment IX and style fused. Penial sheath typical of male Coccidae : fairly long, gradually narrowing to a blunt apex; length 215–250 μm, about 1/6th total body length (ratio of total body length to penial sheath length 1:0.17); width at base 80–85 μm; with strongly sclerotised margins. Basal rod short, 35–43 μm long, anterior end reaching basal membranous area; aedeagus 120–155 μm long, more or less parallel sided with a blunt apex. Apex of style with a cluster of small sensilla and with perhaps 6 short setae along each margin.

Comment. The male of C. serratus appears to be closely related to most of the New Zealand indigenous Coccidae , particularly Aphenochiton inconspicuous (Maskell) and Plumichiton pollicinus Henderson & Hodgson ( Hodgson & Henderson, 2004) which it closely resembles in (i) lacking postmesospiracular setae and (ii) in having rather few setae. It differs from both in having (i) fleshy setae on the abdominal venter, (ii) many anterior and posterior metasternal setae, (iii) many postmetaspiracular setae and (iv) in the presence and structure of the microridges in the reticulations on the head.

The Australian Coccidae are currently being revised (Gullan & Hodgson, in prep.). From this study of the adult females, it is clear that C. serratus belongs to the family Cardiococcinae but it is not congeneric with the type species, Ctenochton viridis Maskell 1879 .

Figures

FIGURE 92. Ctenochiton serratus Green. Macropterous male. (Coccidae). Where A=cranial apophysis, D=fleshy seta, E=hairlike seta and R=dermal reticulations on ocular sclerite.